Yes, it layers just fine. In fact, if you lay down a solid basecoat, you can reduce the amount of prosthetic adhesive mixed into anything painted on top of it. Instead of a 1:1 mix, you can do 1:2 or 1:3.
No promises that the tattoos won't need the odd touch up, but if you don't scrub them off, they will more or less stay in tact.
As long as the paint is acrylic based and listed as nontoxic (most everything sold in the US is), then yes, UV reflective paints work just fine.